Dutch Elm Disease - 2

General Information

• Scientific Name:
  • Ophiostoma novo-ulmi (1)
• Describe the species:

o This is a fungus that effects America Elm trees.(1)

• Life Cycle:
  • Spores of Ophiostoma novo-ulmi are stored in xylem vessels and reproduce through budding. Dispersal of spores is via the bark beetles that burrow under the bark and lay their eggs in wood galleries. Elm bark beetles distribute it locally and over distances for several miles. Beetles bore into the inner bark and while feeding deposit spores Ophiostoma novo-ulmi. The beetles then feed in the crotches of twigs, therefore, most infections occur in twigs. Or bore in the bark of branches and small trunks causing infections in major branches. (3)

Habitat and Distribution
· Where does this organism live?
o It is carried on the backs elm beetles which bores themselves into the trees, easily transporting the fungus to many Elm trees in a short period of time.(1) (2)
· Where has this organism spread to?
o It spread across all Europe, at the same time it was accidentally brought over to the United States and spread dramatically. (2) (3)

Impacts

• Ecological Impacts:
  • It provided remarkable insight into the rapid evolution of plant pathogens outside its endemic environment. (3)
  • It had wiped out around 77 million American elms. (2)

History

• Where did this organism live?
  • It was first recorded on Elm trees in Holland in 1921.(2)
• How did it get here?
  • It was accidentally carried over from France, on the back of a beetle that was living inside elm logs, to Cleveland, Ohio in 1931. (2)
• Where was the first incidence of the species?
  • The disease began its destructive reign in the United States (Cleveland, Ohio) in 1931. (1) (2) (3)
• What where the environmental conditions there?
  • The Conditions in Ohio were very similar to the conditions in France which helped this disease to spread. (3)

Control Measures

• Do we actively try to eliminate these species?
  • Yes, we do. (2)
  • Researchers screened thousands of American elm trees for Dutch Elm Disease (DED) resistance. Enough old specimens were located and kept alive to provide the germplasm necessary to develop DED-tolerant trees. Much of this work was done by Agricultural Research Service (ARS) scientists. (2)
  • Also, insecticides to kill bark beetle vectors are used. Timing of the application may depend on the type of insecticide you have selected. Some insecticides may target the spring feeding sites while others target the over wintering sites and should be applied during late autumn. Use of this management option should be considered carefully. It is difficult to attempt control over this beetle population due to the timing factor, the complete coverage issue, expense and pesticide exposure. (2)

Works Cited

1.) Smith, Catherine A. "Return of the American elm: a beloved classic, long missing from city streets, is starting to make a comeback.(COMMUNITIES)." American Forests. 113. 1 (Spring 2007): 41(5). Student Resource Center - Gold. Gale. Stroudsburg High School. 12 Nov. 2008 <http://find.galegroup.com/srcx/infomark.do?&contentSet=IAC-Documents&type=retrieve&tabID=T003&prodId=SRC-1&docId=A164425071&source=gale&srcprod=SRCG&userGroupName=stro53037&version=1.0>.

2.) Flores, Alfredo. "Dutch elm disease update." Agricultural Research. 54. 6 (June 2006): 18(1). Student Resource Center - Gold. Gale. Stroudsburg High School. 13 Nov. 2008 <http://find.galegroup.com/srcx/infomark.do?&contentSet=IAC-Documents&type=retrieve&tabID=T002&prodId=SRC-1&docId=A147302290&source=gale&srcprod=SRCG&userGroupName=stro53037&version=1.0>.

3.) BRASIER, CLIVE M. "Rapid Evolution of Introduced Plant Pathogens via Interspecific Hybridization." BioScience. 51. 2 (Feb 2001): 123. Student Resource Center - Gold. Gale. Stroudsburg High School. 13 Nov. 2008 <http://find.galegroup.com/srcx/infomark.do?&contentSet=IAC-Documents&type=retrieve&tabID=T002&prodId=SRC-1&docId=A72985115&source=gale&srcprod=SRCG&userGroupName=stro53037&version=1.0>.